Method of making piston rings



1,621,578 R. A. BOOKER METHOD OF MAKING PISTON RINGS Original Filed March 30. 1922 March 22 1927.`

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This invention, which is a division of pplicants co-pendng application, Serial' o.l 548,111', `filedv March 30,1922, has been madethesubject `of a separate application under ocial requirement and relates 'toa new and improved4 method. of making piston rings, and more particiilarly that 'type of ring wherein the`indentations are formed' fin the inner wall ofthe ring, before 'the "ring is losevered, so as to provide uniform radial spring pressu're'when thev ends are sprung apart. ,Y l

Heretofore, it hasbeenthe custom to make resilient piston rings by splitting the rings and then tensioning them by hammering the interior wall thereof sovas to force the split ends apart.

In my improved method, the indentations are formed before the ring is split, so as to 2o displace the molecules overa curved line or area, in contrast tothe wedge or channel impressions heretofore employed. Furthermore, by the present method, the metal is Vdensified in the interior wall of the ring over a substantially lune shaped area, and with blows so varied circumferentially of the ring as to produce the maximumjdensification diametrically opposite a point where the ring is to be split, and gradually diminish- 3o ing the impact ofthe site directions from the point of greatest impact, so as to cause aunifor-m radial spring pressurevwhen the ring is finally severed.

Referring to the drawings wherein is'disclosed a preferred embodiment of the invention:

ing the interior wall of a piston ring peincd in accordance with my invention.

Figs. 2 and 3 are horizontal lsectional views, looking at the inside of the piston ring .at a point diametrically opposite to Fig.

1, and showing, respectively,

and after itis split.

Fig. 4 is a diagrammatic View to illustrate the lune shaped impression formed by the peining tool on the inner wall of the ring. Fig. 5 shows a series of cross-sectional views taken at the points indicated on Fig. 4. Fig. 6 is a side elevation Vof the peining tool showing one manner of forming the peining point. y Fig. 7 is a plan view of the peining tool.

peining tool' in oppo-f Fig. 1 is a horizontal sectional view showl the ring before 1922, serai, No. 548,111. mvra'eaana this" @patatina mea, August 21,1923. serrano. 658,567., v s v l Referring to the drawings,- wherein rlike numerals indicate like parts in the variousl figures, l0 indica-tesa vCircular piston ring having formedin itsinte'rio'r wall 11 a'series;

of' peined indentations or depressions 12, of

substantially lune shape, and so .formed as4 to Vmake `their deepest impression at' the cen-v ,ter .point of thefinterior arc of thel lune,

and gradually andfuniformlydecrease the extent ofthe impression alongy the'interiorl arc ofthe lune as the same approaehesthe apices of that yinterior arc .and the yext i l 1,621,517-

;nrenama- A. Boo-iran, or morirse-nn, iur-IANA, VAssreuon me .nrerrivroamnieren RING terior arc 14 at which. point the ,impression -1 coincides or becomes fiushwith the innerk wall 11 of the ring, as best shown in Figs. 4 and 5. Y i f Y The ring 10 will preferably be marked in any suitablefashion, asat 15, at some point on its inner periphery so `that the peining i or hammering of the ring will be such thatv the maximum impact will be at a point diametrcally opposite this mark 15, and the impact will gradually diminish in opposite directions around the inner circumference of the ring so that the mark 15 will be'appreached on opposite sides by gradually diminishing peining blows.

By marking the ring in this manner the vaction of the peining hammer may be accurately graduated with reference to a certain point, vnamely the point 15, and after peining the ring will be cut at the point 15, as il'- V lustrated in Figure 3, so-that severance of the ring will take place. at the proper point to secure the best results andv anr accurate and uniform expansion.

The peining tool used to carry out my present method, is illustrated in Figures 6 and 7, and is preferably made as shown with a base 16 formed by cutting away one side of the blank 17, of'which the tool is made, and said tool has its peining face 18 formed as a true conical surface sloping uniformlyV in all directions from its' apex 19, which apex is cut away at 20, as shown by a groove, so as to give' a curved base to the-conical vpeining surface from which the lune shaped indentation will be generated upon a blow of the peining tool. This insures formation of the lune .shaped indentation, heretofore described, with its greatest depth at the center ofthe lune and gradually decreasing from the center of its inner arc 13 toward its apices and also outwardly toward its outer arc 14. t

With this tool, and following my method, the peining blow is so distributed that danger of breakage along the peining area is eliminated for the greatest depth and width of the indentation is at the center of the ring and gradually decreases and changes its direction as it approaches the edges of the ring, thus distributing the impact of the peining blow to the indented area and eliminating any stresses which tend to weaken the ring along definite lines.

It is to be understood that the method herein shown and described is to be taken as a preferred embodiment of the same, and that such changes in construction and arrangement of parts as fall within the purview of one skilled in therart may be made without departing from the spirit of the invention and the scope oi the claims.

l. The method of peining piston rings, which consists in densifying the metal in the interior wall of the ring over a substantially lune shape area so that the impression will have its greatest depth and width at the center point of the interior arc of the lune, said impression decreasing gradually and uniformly towards the apex of the interior and exterior arcs of the lune, and then splitting the ring.

2. The method of peining piston rings, which consists in densifying ythe metal in the interior wall ot' the ring over a substantially lune shaped area and with blows so varied circumferentially of the ring as to produce the maximum densication at a point opposite to where the ring is to be split, and gradually approaching the minit mum at the ends so as to produce a perma- A nently circumferentially varied distortion of the metal, and a uniformly radial spring pressure when the ring "is split, and then splitting the ring.

In testimony whereof I have hereunto set my hand.

RICHARD A. BOOKER. 

